Fiberboard containing bitumen modified fatty acid pitch



Patented May 5, 1953 UNITED STATES PATENT OFFICE FIBERBOARD CONTAINING BITUMEN MODIFIED FATTY ACID PITCH 1 Leonard Charles Bradshaw, Slough, England, as-

. signor to International Bitumen Emulsions Limited, Slough, England, a company of Great Britain and Northern Ireland No Drawing. Original application September 17,

1946, Serial No.

697,597, now Patent No.

Section 1, Public Law 690, August 8, 1946 Patent expires July 31, 1965 The subject of this invention is a rigid, non flexible, bituminized fiber board made by the method of manufacture forming the subject of United States patent application Serial No. 697,597 dated'September 17. 1946, now Patent No. 2,602,029, granted July 1, 1952, of which the present application is a division.

Since it is an essential part of the invention that the articles shall undergo baking treatment, it is necessary to modify this baking treatment, and the compos tion of the bituminous material to conform with the heat resistance of the fibrous material being used. In the following description of the invention asbestos fiber has been taken as an example of the fibrous material, as its heat resistance allows of considerable scope in the maximum baking temperatures which can be used, thereby reducing the necessary period of baking. It is to be understood, however, that the invention is not limited to the use of those fibrous materials which will withstand the temperatures mentioned, since it is practcable to use fibrous material which would undergo deterioration at those temperatures (for example, paper), by carrying out the baking operation at lower temperatures for longer periods.

In accordance with the present invention, therefore, the bituminous material is modified by fluxing with it a proportion of fatty acid pitch; the term fatty acid pitch includes such substances as pitch, stearin pitch, bone tar pitch and the like and residues from the distillation of oils, and known in commerce as vegetable oil residues, all of which can be made to polymerize when ex osed to suitable conditions of temperature and time.

The suitably modified bituminous material is then emulsified in the manner to be described.

Alternatively, emulsions may be made of a bituminous material and of the modifier, and these two emulsions'mixed prior to the addition to the fibrous material, or they may be introduced separately.

In certain cases, 'to accelerate the ultimate hardening sulphur and suitable accelerators may be incorporated either in the internal or external phase of the emulsion.

It has been'found that in blending the bituminous material w th the polvmerizable material, the penetration of the blend may be so high that. when converted to an emulsion and used in the process. as specified, trouble may be caused after the formation of the web by the *eb adhering to the pick-up rollers, felts and the like.

In such cases, it is a part of the invention to overcomethis disadvantage by the conversionof all 3 Claims.

or part of the fatty acid radicles in the polymerizable material to heavy metal or alkaline earth soaps before the emulsification of the blend.

Example of emulsions which can be used in the invention are given herewith:

Example 1 parts by weight of vegetable oil residue are heated with 20 parts by weight of zinc oxide for 30 m nutes at 200 C. 240 parts by weight of Trinidad As halt are then added and the whole stirred, the temperature being maintained until the mixture is homogeneous. The flux is then cooled below 150 C. and 18 parts by weight of sulphur stirred in. This blend is then emulsified by running 150 parts by weight thereof into 50'parts by weight of hot water conta ning 5 parts by weight of sodium metasilicate and 1 part by weight of potassium hydroxide. The emulsion so formed is diluted with hot water to a total out-turn of 300 parts by weight.

Example 2 An emulsion produced as described in Example 1 but with the Trinidad Asphalt replaced by an equal uantity by we ght of 15/25 penetration straight run petroleum bitumen.

Example 3 An emulsion produced as described in Example 1 but with the Trinidad Asphalt replaced by an equal part by weight of C.- C. softening point B. & 13., straight run petroleum bitumen.

Example 4 An emulsion produced as described in Example 1 but with the vegetable oil residue replaced by equal parts by weight of medium soft stearin pitch- Example 5 An emulsion produced as described in Example 1 but with the vegetable oil residue replaced by equal parts by weight of vegetable oil pitch.

Example 6 An emulsion produced as described in Example 1 but omitting the sulphur.

Example 7 ample 1.

3 Example 8 Parts'by weight Medium coal tar pitch 200 Trinidad asphalt 100 Soft vegetable pitch 150 Sulphur 36 10% Bentonite slurry Caustic soda 9 Water 130 The emulsion so formed is diluted with hot water to givean out-turn of 300 parts byweight.

.The formation of these emulsions is, of course, modified according to the fibrous material'to be used, which lar ely determines the ultimate .tem peratures of baking.

An example'of a manufacturin process which may be used to producethe articles covered by this invention is as follows:

' (Utilising a single .vat board-machine, Grade 46 asbestos is beaten in water for 30 minutes, the concentration of asbestos bein't At t e end of ithis'period the emulsion isrun into the beater. It is found that the most thorough dispersion is obtained when the emulsion is added to the stream'of asbestos .pulp just before it flows under the beater .roll. Suiiicientemulsion is added to give-a pu p containing equal parts of asbestos andbituminous-pitch binder composition. Beating is continued with the beater roll raised, until the emulsion has been thoroughly dispersed throu h thepulp. A um num:sulnhatesolutionis 11 then added in sufiicient quantity completely to precipitate the bitum nous materials on the asbestos fibers. After the precipitation process is completed..the.mix is diluted in the stuff chestto a consistency" of between 0.5% and 1.0% solids. It is then fed in .the usual manner to the board machine, from which sheets of any desired thickness may be taken offin a semi-dry condition. The -board"so produced-in a semi-dry condition may be formed'into corrugated sheets, sheets, tubes, ormoulded into various shapes. They may be'pressed and moulded under pressure.

It is an essential part ,of the drying process which follows that it shouldbe gradual at first, the temperature 'not exceeding, say 90 .C and the heating being carried .out in the presence ,of an adequate air flow, in order to remove the water without fluxing .the bituminuous material. If this condition is not observed, water will be trapped within the material and blistering will occurduring the subsequent baking. After being subjected to the dryin". process, the artic es'or sheets are baked at ahigheintemperature (150 C. to 170 C.) for a number of hours, according to the class or finish reouired. In certain casesit may be desirable to finish with a further'hot pressing.

As an alternative to the above, the sheetsin the semi dry condition may be passed and subjected immediatelyto the low temperature dryin'r previously described. Having been dried, the sheets may then be formed into corrugated sheets, tubes, or moulded shapes whilestill warm, with or without theuse of hot presses, and thengiven the ultimatebaking treatment. As an example of this baking'treatment, temperatures of 0.- C. over a period of 7 hours may be used.

It is emphasised that the baking treatment will depend upon the desired finish, as hardening will increase with continued baking.

'If desired'the sheets may be moulded into the required shapes during or at the end of the baking period while they are still hot.

Alternatively, if the machine be a continuous one, the board may'be dried at low temperatures, reeled up and stored in this condition until it is required for moulding and ultimate baking.

It is practicable to apply baking enamels to the articlesat' the interim stage during baking to produce special decorative or protective finishes.

Shodldit not' be desired to add the modified bituminous emulsion to the fibrous pulp in certain cases,the emulsion may be applied to the semidry or dry board, and the board subjected to low temperature drying to remove the water and allowthe bituminous material to penetrateinto theboard before itis subjected tothe ultimate baking. In carryin out this process, it may be necessary to repeat the'coating and drying several times, according .to the quantity of bituminous material required in thefinal product.

Another 1 application of the invention is the fabrication of articles at present made from the papier machine processesirom theboard either in the dry or semi-dry condition.

When fully baked, the material is water resistant, petrol and oil resistant, of considerable rigidity and strength, and can be usedfor corru ated sheeting for roof work, floor tiles, insulation, building and other miscellaneouspurposes.

.I claim:

1'. Arigid, non-flexible, bituminized, fiberboard consisting essentially of approximately equal amounts-of fibrous material and a'polymerized and vulcanized binder of fatty acid 'pitch'modi-' fied witha hard bitumen, the ratio of fatty acid pitch vto bitumen in the binder being to 2.4 and 3.5to 1.

2. A rigid, non-fiexible,.bituminized,fiber board as defined in claim 1 -in which the amountof bitumen in the binder'isbetween 2xto 2:4'times" the amount of fatty acid pitch. 1

3. Arigid,;non-fiexible,bituminized, fiber board as defined inclaim .1 in which the major portion of the fibrous material'is asbestos fibers.

LEONARD CHARLES BRADSHAW.

Dat

Dar-rah May 3, 193,2 Lo etscher June 1'4, 1932 Ellis .Margfl, 193.3 Pieper Mar. 21, 1933 Keller May ,1, 1934 Batcheller Dec..13, 1938 'Wood Apr. 23, 1940 Bernstein et 'al 'Nov. 17,1942 Cross 'J an. 11, 1944 Bruce 'Oct.i17, 194i .iroREIGN PATENTS Number Country Date Great Britain: "34 M125, 1931 between 1 Field May'16, 1876 Van Westrum Apr..2.6, 1910v Stanley iJune'27, 1922',

.Great Britain ;Sept. 19', 1929 

1. A RIGID, NON-FLEXIBLE, BITUMINIZED, FIBER BOARD CONSISTING ESSENTIALLY OF APPROXIMATELY EQUAL AMOUNTS OF FIBROUS MATERIAL AND A POLYMERIZED AND VULCANIZED BINDER OF FATTY ACID PITCH MODIFIED WITH A HARD BITUMEN, THE RATIO OF FATTY ACID PITCH TO BITUMEN IN THE BINDER BEING BETWEEN 1 TO 2.4 AND 3.5 TO
 1. 